This invention relates to a wheel rim and method of constructing such a wheel rim that assists in seating of the tire.
A wheel rim construction should be designed to permit easy mounting of the tire, yet should also insure against movement of the tire bead relative to the wheel rim once mounted and inflated. Various wheel rim configurations have been proposed for achieving this purpose. In addition to the aforenoted desired results, the wheel rim should permit easy disassembly of the tire for servicing or replacement. Substantially all of the wheel rim constructions are a compromise to achieve all of these effects. It is also desirable for the rim to cooperate with the tire bead in such a way as to prevent the tire from leaving the rim in the event of a "run flat" condition. That is, it is desirable for the tire to remain on the rim even though it is fully deflated so that the owner may drive the vehicle to a place where it may be serviced.
U.S. Pat. No. 3,977,727 issued to William A. Glasenapp et al, teaches two ways in which a wheel rim may be modified to prevent a pneumatic tire from disengaging the rim upon the loss of air pressure. Glasenapp teaches cutting "barbs" into the tire bead seat portion of the wheel using a chisel type tool or as an alternative, cutting circumferential "knurls" into the bead seat. By both of these techniques the cutting operation removes metal from below the intended bead seat surface thereby weakening the rim structure in the bead seat region.